Blasting stone



M 0 G. M. GITHENS. v

BLASTING STONE.

No. 479,500. Patented July 26, 1892.-

UNITED STATES PATENT OFFICE.

GEORGE M. GITI-IENS, OF BROOKLYN, NE\V YORK.

BLASTING STON E.

SPECIFICATION forming part of Letters Patent No. 479,500, dated July 26,1892.

Application filed January 2, 1892. Serial No. 416,756. (No specimens.)

To all whom it may concern.-

Be it known that I, GEORGE M. GITHENs, a citizen of the United States,residing at Brook lyn, in the county of Kings and State of New York,have invented an Improvementin Blasting Stone, of which the following isa specification.

In blasting out stone in quarries it is desirable to split the stone asnearly straight as possible and to prevent loss of stone resulting fromlarge drill-holes or from powder-cracks.

My present invention is especially available in sandstone-quarries andwith other stone that is in layers of greater or less thickness.

In quarrying this character of stone it is usual to drill a range orranges of holes in the line of cleavage and to drive in plugs or wedgesand feathers to split the stone. These, howover,have always been appliedat the surface of the stone. Hence the crack has been commenced at thesurface and extended downwardly, and where the beds of stone rest firmlyone on the other the crack, instead of passing down vertically, oftenextends diagonally and runs out at the vertical face of the ledge,because this is the line of least resistance. I have discovered thatafter a hole is drilled to a suitable depth and a sharp chiselpointeddrill is driven into the stone at the bottom of the hole and a blast isfiredin such hole the stone will be split in the line that is marked bysuch chisel. This appears to arise from the fact that a crack is startedin the stone by the chisel and that the force of the explosion continuesthis crack; and my present invention relates to the method hereinafterdescribed and claimed for carrying out my invention or discovery.

In the drawings, Figure 1 illustrates by a section of the rock themanner of preparing each drill-hole. Fig. 2 is a similar view with thewedges in place, and Fig. 3 shows a range of holes prepared for firingand at right angles to Figs. 1 and 2.

The drill-holes a. a, are inserted in the line of cleavage, and insandstone and stones having natural beds or layers these drill-holes arenot extended down to the natural bed or seam b, at which the cleavage isto terminate, but such holes are sufficiently above to prevent injury tothe strata below the seam. A properly-sharpened drill is now introducedinto the holes in succession, and it is marked on one side or so guidedthat the straight chisel edge of the drill is in the line of the desiredcleavage, and this drillis driven down by a suitable sledge or otherwisewith sufficient force to embed the chisel edge into the rock, as at c,and thereby commence the line of cleavage. If now powder is introducedinto the hole thus prepared and exploded, the rock will be broken in theplane, or nearly so, of the chisel-mark in the bottom of the hole. Iavail myself of this feature in carrying out my invention, as follows:

Into a range of holes drilled to the proper depth, as aforesaid, thewedges d d are introduced, and the keys or plugs e are driven in betweenthem. This is preferably accomplished by small charges of powder in eachhole, exploded simultaneously by electricity or otherwise. I have shownthe powder at f, which may be in canisters or poured into the hole abovewads g, resting on top of the tapering plugs e, and it is usuallyadvantageous to leave air-spaces in the holes above the powder and toplug the upper ends of the holes.

By this improvement the crack is commenced at c and continues down tothe bed or seam b and tends to lift the rock as it is split from thebed, and the split continues upwardly to the top, and the piece of stoneis thus split with accuracy and'moved bodily outwardly on the uninjuredbed-rock, and the extent of movement given to the rock depends on thequantity of powder, and when cleavage is effected in the same manner,and

the wedges are operateduntil the stone is moved off bodily and the crackopened at the top the desired distance.

In consequence of the cleavage being commenced at the bottoms of theholes and near the bed or seam there is a lifting action to lift thestone from the bed instead of forcing the stone down upon the bed, as isthe case when the splitting action is commenced near the top of thestone. The wedges are not materially injured by use and can be recoveredafter the stone is sufficiently removed.

In the usual manner of firing explosive ma terial in a blast thepressure is uniform and radial and the cleavage is in the line of leastresistance and the downward pressure at the bottom of the hole isvalueless in the splitting operation. By placing the wedges in thebottom of the hole the downward pressure is availed of in splitting thestone in the line of cleavage thatis predetermined by the position ofthe wedges.

I claim as my invention 1. The method herein specified of splittingstone, consisting in drilling a hole into the stone to the place Wherethe cleavage is to be commenced, then driving a straight-edged chiselinto the stone at the bottom of the hole to start a fracture in the lineof cleavage, then continuing the separation by pressure within the hole,substantially as set forth.

2. The method herein set forth of splitting stone, consisting indrilling holes into the stone in the line of cleavage, driving into thestone at the bottom of each hole a chisel to start the fracture in theline of cleavage, and continuing the splitting action by wedges Withinthe bottoms of the holes, substantially as set forth.

3. The method herein set forth of splitting stone, consisting indrilling holes into the stone in the line of cleavage,driving into thestone at the bottom of each hole a chisel to start the fracture in theline of cleavage, and introducing into such holes wedges and explosivematerial to act on such Wedges and split the stone, substantially as setforth.

Signed by me this 30th day of December, 1891.

GEO. M. GITI-IENS.

Witnesses:

GEO. T. PINOKNEY, ALICE M. OLIVER.

